7
votes
Explanation of Quadcopter Dynamics, Components and Control
A couple things, the first is that the controller does not really care what the "real" values are. Everything is relative, if the controller sees that it is sinking it will increase the thrust until ...
- 1,919
7
votes
Accepted
Using brushless motors for very high torque
Your expectations are rather aggressive for a DC motor.
First - 40Nm (350in-lbs) is A LOT of torque! Ex: A max rated torque for 1/4-20 bolt is only 75 in-lb (8.5Nm).
Second - The mechanical power ...
- 705
6
votes
What are some ways to estimate torque/load on a robotic arm joint
Model Based:
Low cost solution is always software:
Develop a dynamic model which computes the load on the motors based on the motions (e.g. with Recursive Newton Euler Algorithm or Lagrange-Euler ...
- 6,652
4
votes
Accepted
How to control ESC from Arduino?
There are quite a few issues I see with your setup.
You are setting up the ESC in your code to use pin 9, but your diagram shows that you've connected to pin 8. Pin 8 won't do anything because the ...
- 16k
4
votes
Accepted
Will increasing voltage on brushless DC motor increase torque, if speed is kept constant?
It depends on various other factors as well. If the motor outputs 60RPM @24V under load, given the motor is rated for 12V - 60V and the load is kept the same, then by doubling the voltage from 24V to ...
- 71
3
votes
Accepted
What is the typical weight distribution for a brushless motor?
I took apart a Turnigy D2836 brushless DC motor. Despite the weight listed on the website, the actual weight of the motor without the mounting equipment is 54 Grams.
Here is the breakdown
Magnets: 9 ...
- 195
3
votes
Can i use DC Brushed motors for building a drone?
I would definitely look at a brushed motor when the budget is low. They have a reputation of being less powerful, but the main problem is they have a very high RPM. This means you either have to use ...
3
votes
Electronic Speed Controller
It depends on the voltage.
Say you are running 12V:
1820W / 12V = 151A
With a 24V system:
1820W / 24 = 75A
- 251
3
votes
Accepted
Do mobile robots use variable transmissions?
For a simple answer: no, most mobile robots do not use variable transmissions. I believe it is far easier to just design a motor and gearbox combination that works well in your narrow range of ...
Ben♦
- 5,825
3
votes
How to avoid oscillations caused by backlash in position control?
Backlash is only an issue when you change directions, because that's when you'll open the space in the gear train. If you're using PID control, consider an overdamped response instead of a typical &...
- 16k
2
votes
How to calculate the current consumed by a brushless motor on a quadcopter
n = Kv * Vin only when there is no load on the motor. When there is a load on the motor, like from a propeller, you will need to be a bit more clever.
For a DC motor (which BLDC motors approximate by ...
2
votes
Accepted
Bldc motors erratic behavior with Arduino program
Can you make a written description (comments, text, or block diagram) of what you think the code is supposed to be doing?
I can't figure out what your whole timer scheme is supposed to do. Here's ...
- 16k
2
votes
How to find Friction or Viscous force b (nmsec) in DC motor
When no other load is on the motor, any torque that the motor is producing is to overcome the friction. If you know how to calculate your friction from the torque needed to overcome it (I don't), then ...
- 331
2
votes
How do I if know my quad is powerful enough to take off vertically smoothly and how do I calculate max Thrust(g) for given current(A) and voltage(V)?
You're really asking two questions here:
Will the motors and propellers be able to provide enough thrust to lift the weight of the quadcopter?
There's no substitute for measurement here. Get one ...
- 11k
2
votes
Why the bldc motor not able to move my water boat?
It sounds to me like you've got cavitation. Basically, the blades are turning so fast that the water around the blades boils. Boiling can happen at normal pressure and high temperature, like on a ...
- 16k
2
votes
Accepted
Confirm my understanding on BLDC motors
Now if i power the ESC with 48V instead of 16V and set it to 33% instead of 100% The effective voltage on the motor is still 16V and the motor will still use 48W, but since the ESC is getting 48V it ...
- 4,385
2
votes
Explanation of Quadcopter Dynamics, Components and Control
You're right. You should know the rpm of your propellers to build a mathematical model of your quadcopter and if you already have a mathematical model of your brushless DC motors you could compute ...
- 121
2
votes
Why does the ESC stop?
First of all I would suggest calibrating them.
From the eBay page you linked to, It would seem that the ESCs are probably HobbyWing (or HobbyWing clones). I would suggest finding some spec sheets for ...
- 1,047
2
votes
Accepted
Is a larger Kv equivalent to more voltage?
OK so lets start with Please correct me if I'm wrong
As I understand, a brushless motor has a maximum torque and power (Watts), if you push it beyond its limits ...
- 705
2
votes
Are all drone propellers compatible with all brushless motors?
Not at all. It is about efficiency, agility, and maneuverability of your drone.
Just like wheels on a car, the size of the propeller needs to be matched to the rest of the power system. For ...
- 96
2
votes
Is it uncommon to use a gearbox with a brushless motor?
Yes, brushless and grearbox is a normal usecase. Due to the popular application of using brushless motors on drone propellers other applications are harder to find. The keywords "Brushless ...
- 6,652
2
votes
Accepted
wheeled vehicle forward velocity from RPM brushless data
This project does exactly that on an RC car. The author is a top competitor in the DIYRobocars community; it's the blue car in this video. He uses tachometry from the brushless motor, an IMU and ...
- 356
2
votes
DRV8833 Motor driver connected to four raspberrypi zero V1.3 GPIO pins causes motor movement to fluctuate despite setting all pins to OFF
This sounds like you're bringing the chip out of sleep mode before your GPIO pins are set up. Until they are set up, their behaviour will be undefined.
The nSLEEP pin is pulled low with a 500k$\Omega$ ...
- 4,243
1
vote
Is a larger Kv equivalent to more voltage?
It is helpful if you think of this in terms of overall power, rather than just voltage.
Imagine you have a machine which requires 100W per motor for your desired flight performance characteristics. ...
- 11
1
vote
Accepted
Motor for DIY Electric skateboard
Check the legal requirements of the motors for your area.
The little 1000kV motors wouldn't have sufficient torque...
Look for anything below 600kV and the motor should be equal to or under the ...
- 248
1
vote
Motor for DIY Electric skateboard
The 1000kv motor will probably not have enough torque, and the 10A motor will drain your battery (I am assuming you will be running on a battery) way too fast.
The motors you want are a lower kv that ...
- 157
1
vote
Brushless DC motor problems at high velocities
Nice detail in your question.
The somanet site makes a big deal about their firmware being open source, so you should be able to check the timing in the code (or otherwise get the help of the somanet ...
- 4,385
1
vote
Driving sensorless three phase BLDC motor with Arduino and IMU
consider coupling the motor with an encoder that has enough resolution to tell you precisely when to ramp up current to a particular phase. this will give you precise feedback to develop a control ...
- 11
1
vote
What are some ways to estimate torque/load on a robotic arm joint
50k4 did a good job of enumerating the different ways to measure torque in the joints. So I won't go into that. But if you want to detect unexpected impacts, another option is to use accelerometers. ...
Ben♦
- 5,825
1
vote
Torque / Current control for BLDC motors
You did not exactly specify the application you are working on, however, the fact that you have limited angular displacement range, and not continuous rotations, does not necessarily mean that you ...
- 6,652
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